Several years ago I bought a 12-volt Dewalt Drill. In the beginning I used it infrequently, so I wasn’t especially surprised that the batteries were almost always down. I’d charge them up, use them for a day or two and put them away again. It was only some considerable time later as I began using the drill more frequently that I realized neither battery would hold a charge – even when unused – for more than a few days. I know! I should have taken it back – but I didn’t. I finally assumed I simply had a couple of lousy batteries – but with both batteries displaying the same problem, I’m now suspicious of the charger. A number of Years ago I gave away two perfectly good Delta batteries to my brother that behaved similarly. Using his charger, those batteries fully charged and held the charge well. My question is – how can I determine where the problem lies?

Thanks for your input. You may be exactly right, but two things make me suspicious of the charger. First, the charger was the problem I had with the Delta, and second, it strikes me as odd that the length of time the unused batteries hold a charge is very similar. It would be a simple matter to check if I knew someone with the same batteries and charger as mine. Unfortunately I don’t, and I was hoping someone would know of another way to check.

Cold really drains these batteries, especially if they are old. Most likely its time to replace them and the sad part is, It cost about the same to replace the 2 batt’s as buying a new drill with batteries. The charger could have a pinched or lose wire inside, but I doudt it.

Tool batteries have several cells wired in series. All cells inside a battery discharge at different rates. As they discharge, the most highly charged cell can reverse the voltage that another cell sees and effectively ruin it. After that, your battery is no longer a 12V battery – it’s 10.8V battery. Keeping your batteries charged at all times helps immensely. Also, never run the tool until the battery just won’t make it go anymore at all. That’s really bad. When you think the battery is starting to run low, STOP and recharge it. I agree with CampD, the cost of replacement batteries is hideous. It seems to always come to decision of whether to buy new batteries or a new tool, and it’s never easy.

What type of batteries are they? Are they the nicad batteries? The reason that I ask is that with a nicad battery, it develops a memory and if you dont totally discharge it from time to time, it wont fully charge anymore. My Porter Cable 19 V drill has nicads, and I typically will run them way down before charging…of course there is a point where the drill wont have any torque anymore, so you have to charge them, but I let them run way down. I have had the drill for many years and they charge up just fine and will hold a charge for many months if not used.

I’ll second SnowyRiver in that getting the most use out of Nickel Cadmium batteries you need to run it down before you throw it on the charger. Your batteries might be junk, but remember to get them low before you recharge. Lithium Ion batteries don’t have this problem.

I appreciate the thoughts and suggestions. The batteries are NiCad. I’ve just learned from re-reading the instructions that the light on the charger is supposed to provide various information depending on the frequency and duration of the flash. A regular spaced flash, for instance means normal charging – rapid flashing means a weak battery that needs replacing – constant on means fully charged. Mine never shows a weak battery, and currently shows normal charging. Unless it’s different from past experience, it will show fully charged when I check it in the morning. Despite that, within days (even without use), it will be dead flat – not even enough charge to rotate the chuck. My nearest service center is about 50 miles away, but I guess that’s my best bet.

I have the same tool , Dave …..it’s the batteries : ( I have THREE chargers and get the same results on each battery no matter which charger I use. I’ve spent countless hours online trying to find the “best price” on replacement batteries and found out that there are several different Amp Hour ratings to choose from , so you have to decide how much you use your tool and how much you want to spend on batteries.

NiCad batteries have some real bad habits and they get worse with age.I would suggest you check this website for a comprehensive review of this type & what to consider regarding restoration vs. replacement.hope this helpshttp://www.angelfire.com/electronic/hayles/charge1.html

Dave, I have the 12 volt DeWalt drill as well, and if you bought it several years ago you would have fallen under the charger recall for the DeWalt chargers for the 12 volt. If I recall correctly the problem was that they overcharged the batteries causing excessive heat build up and creating a fire hazard. So they recalled the chargers and sent out new ones to those who responded to the recall. Unfortunately I don’t recall hearing of anyone getting free battery replacements in that recall. Needless to say I pitched that drill and have never bought another DeWalt product since. That’s not to say that I didn’t have other issues with that model drill as well.